Source code for snipskit.mqtt.decorators

"""This module contains decorators_ to apply to methods of a
:class:`.MQTTSnipsComponent` object.

.. _decorators:

By applying one of these decorators to a method of a
:class:`.MQTTSnipsComponent` object, this method is registered as a callback to
the corresponding event. When the event fires (e.g. an MQTT topic is
published), the method is called.


.. code-block:: python

    from snipskit.mqtt.apps import MQTTSnipsApp
    from snipskit.mqtt.decorators import topic

    class SimpleSnipsApp(MQTTSnipsApp):

        def hotword_on(self, topic, payload):
            print('Hotword on {} is toggled on.'.format(payload['siteId']))

import json

[docs]def topic(topic_name, json_decode=True): """Apply this decorator to a method of class :class:`.MQTTSnipsComponent` to register it as a callback to be triggered when the MQTT topic `topic_name` is published. The callback needs to have the following signature: method(self, topic, payload) Args: topic_name (str): The MQTT topic you want to subscribe to. json_decode (bool, optional): Whether or not the payload will be decoded as JSON to a dict. The default value is True. Set this to False if you want to subscribe to a topic with a binary payload. """ def wrapper(method): def wrapped(self, client, userdata, msg): """This is the callback with the signature that Paho MQTT expects. """ if json_decode: payload = json.loads(msg.payload.decode('utf-8')) else: payload = msg.payload # This is the callback with the signature that SnipsKit expects. method(self, msg.topic, payload) wrapped.topic = topic_name return wrapped return wrapper